{VERSION 5 0 "IBM INTEL NT" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 0 2 2 2 0 0 0 0 0 0 1 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "T itle" 0 18 1 {CSTYLE "" -1 -1 "" 1 18 0 0 0 0 0 1 1 0 0 0 0 0 0 1 }3 0 0 -1 12 12 0 0 0 0 0 0 19 0 }{PSTYLE "R3 Font 0" -1 256 1 {CSTYLE " " -1 -1 "Helvetica" 1 12 0 0 0 0 2 1 2 0 0 0 0 0 0 1 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "R3 Font 2" -1 257 1 {CSTYLE "" -1 -1 "Couri er" 1 12 0 0 0 0 2 2 2 0 0 0 0 0 0 1 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 18 "" 0 "" {TEXT -1 27 "MAPLE WORKSHEET for SERIE S " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 452 "\nThis worksheet is intend ed to provide a graphical interpretation of sequences and their limits . The Series command provides the following information:\n i ) numerical values for the first N partial sums of the series;\n \+ ii) the sum of the series, if it converges;\n iii) a plot \+ of the first N partial sums of the series.\n\nREMEMBER: Do NOT confuse the sequence of partial sums and the sequence formed by the terms of \+ the series.\n" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "with(plots):" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 95 "The simplest way to figure out sum of an infinite series is by using 'sum' Maple syntax below. " }} {PARA 0 "> " 0 "" {MPLTEXT 1 0 26 "sum(1/n^2, n=1..infinity);" }} {PARA 0 "" 0 "" {TEXT -1 0 "" }{TEXT -1 172 "The 'Sequence' and 'Serie s' below are defined by a procesure. The first step is to define the M aple procedures for displaying series (and sequences) in a convenient \+ manner." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 441 "Sequence := proc( expr, arg::name=range )\n local f, i, ii, S, var, lo, hi, m, M;\n var : = lhs(arg); lo := op(1,rhs(arg) ); hi := op(2, rhs(arg) );\n f := un apply( expr, var );\n S := [seq( [i, evalf(f(i))], i=lo..hi )];\n \+ m := min( 0, seq( op(2,s), s=S ) );\n M := max( 0, seq( op(2,s), s=S ) );\n print( S );\n print( Limit( f(var), var=infinity ) = limit ( f(ii), ii=infinity) );\n plot( S, var=lo..hi, y=m..M, style=POINT \+ );\nend:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 529 "Series := proc ( expr, arg::name=range )\n local f, i, ii, j, P, s, var, lo, hi, m, M;\n var := lhs(arg); lo := op(1,rhs(arg) ); hi := op(2, rhs(arg) ) ;\n f := unapply( expr, var );\n s := 0; P := NULL;\n for i from lo to hi do\n s := s+f(i);\n P := P, [i, evalf(s)];\n od; \n P := [P];\n m := min( 0, seq( op(2,p), p=P ) );\n M := max( 0 , seq( op(2,p), p=P ) );\n print( P );\n print( Sum( f(var),var=lo ..infinity ) = evalf( sum( f(ii), ii=lo..infinity ) ) );\n plot( P, \+ var=lo..hi, y=m..M, style=POINT );\nend:" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 224 "The first few examples focus on the distinction between \+ the sequence of partial sums and the sequence of the terms of the seri es. First, here are the first few terms of the sequence formed by the \+ terms of the series \{a[k] \}." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 33 "S equence( 100*(1/2)^k, k=1..37 );" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 147 "And, here are the first 50 partial sums (numerically and graphica lly). Notice that, in this case, both sequences converge, but to diffe rent limits." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 31 "Series( 100*(1/2)^k , k=1..37 );" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 106 "Now, for some mo re geometric series. First, here's a geometric series with r>1 (what s hould happen here?):" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "Sequence( 2 ^(k-1), k=1..10 );" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 28 "Serie s( 2^(k-1), k=1.. 10 );" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 41 "This i s an example of a divergent series." }}{PARA 0 "" 0 "" {TEXT -1 182 "T his geometric series is also divergent, but in a different way. Note t hat the sequence of terms alternates between 1 and -1; the sequence of partial sums alternates between 1 and 0." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "Sequence( (-1)^(k-1), k=1..10 );" }}}{EXCHG {PARA 0 " > " 0 "" {MPLTEXT 1 0 30 "Series( (-1)^(k-1), k=1..10 );" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 144 "These two examples illustrate the n\{th \} Term Test for the DIVERGENCE of a series. Since the terms do NOT co nverge to 0, the series MUST DIVERGE." }}{PARA 0 "" 0 "" {TEXT -1 324 "Think about what the n\{th\} Term Test is saying. A series converges \+ when you can add an infinite number of numbers to obtain a FINITE answ er. If the individual terms do not become small (converge to 0), the s equence of partial sums will keep changing by this (not small) amount \+ and so cannot be converging to a finite number." }}{PARA 0 "" 0 "" {TEXT -1 179 "The converse of the n\{th\} Term Test does NOT apply. Ju st because the terms converge to 0 does NOT IMPLY the series converges . The classical counter-example is the Harmonic Series:" }}{PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 25 "Sequence( 1/n, n=1..50 );" }}}{EXCHG {PARA 0 " > " 0 "" {MPLTEXT 1 0 23 "Series( 1/n, n=1..40 );" }}}{EXCHG {PARA 0 " " 0 "" {TEXT -1 309 "The Alternating Harmonic Series is a different st ory. Here the terms converge to 0, and the series converges. Notice ho w the partial sums bounce back and forth. With each partial sum, the a mplitude of the oscillation decreases; ultimately, the sequence of par tial sums does converge (but not to a nice value)." }}{PARA 0 "> " 0 " " {MPLTEXT 1 0 28 "Series( (-1)^n/n, n=1..40 );" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 29 "Series( 2/(k-1)/k, k=3..85 );" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 912 "SUMMARY:\n\n There have been three main points to this demonstration.\n\n1. Notice \+ the distinction between the sequence of partial sums and the sequence \+ of terms of the series. The partial sums are difficult to find, in gen eral. We will be developing techniques which permit us to make a concl usion about the sequence of partial sums (and\nhence the series) while examining only the terms of the sequence. Please, work hard to unders tand this difference.\n\n2. The n\{th\} Term Test is a simple test tha t enables us to examine the terms of the series to determine when some series diverge. This should be the first test that you apply to any s eries. Here's another statement of the n\{th\} Term Test:\n if lim a [n] <> 0 then the series MUST DIVERGE\n if lim a[n] = 0 then the ser ies MAY CONVERGE (but some other test will have to be used to decide) \n\n3. Geometric series converge only when the radius satisfies: -1 < \+ r < 1." }}}}{MARK "3 0 0" 87 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 } {PAGENUMBERS 0 1 2 33 1 1 }